Posts Tagged ‘linux’

OpenSSL Client Commands – Check the Contents of an SSL Certificate

March 7th, 2014 No comments

Here are a list of useful OpenSSL commands which might be useful to use in a Bash script:

Determine who issued the certificate:
$ echo | openssl s_client -connect 2>/dev/null | openssl x509 -noout -issuer
issuer= /C=US/O=Company Inc/ Read more…

Categories: SSL/TLS Tags: , ,

Simple Bash Script to Backup Netscreen ISG / SSG Firewall

November 7th, 2013 No comments

This script is a simple, interactive way to backup and date-stamp your juniper Netscreen ISG/SSG (ScreenOS) firewall configurations. The script copies the configurations from the firewall using scp. Configurations older than one day ( -mtime +1) are archived off to a bz2 compressed file.  Archives older than 60 days ( -mtime +60 ) are removed from the disk.

The usage is: [ip address / hostname of Netscreen].  (VIEW SCRIPT)

Read more…

Running Snoop on Netscreen Firewall

September 26th, 2013 No comments

An aide-memoir:

ScreenOS-> undebug all
ScreenOS-> clear db Read more…

Categories: Juniper, linux, Security Tags: ,

Linux Command – Primer / Aide-Memoir

November 17th, 2012 No comments

System Shut Down
shutdown -h now (Displays the file hello.txt)
shutdown -h +15 (Displays the file hello.txt)
shutdown -r now (Shut Down > Restart now)
shutdown -r +15 (Shut Down > Restart in 15 minutes)

IP Configuration (Edit the ifcfg-eth0 file):
cat /etc/sysconfig/network-scripts/ifcfg-eth0     View the configuration file for eth0
vi /etc/sysconfig/network-scripts/ifcfg-eth0     Edit and Save the configuration file for eth0 Read more…

Categories: linux Tags:

The Story of Linux

January 23rd, 2012 No comments

A video from The Linux Foundation, commemorating 20 Years of the Linux Operating System: Read more…

Categories: linux Tags:

Understanding the Linux Startup Processes

August 17th, 2011 No comments

This is a link to a brief description of what happens in a Linux system, from the time that you turn on the power, to the time that you log in and get a bash prompt. Understanding this will be helpful when you need to solve problems or configure your system.
Greg O’Keefe,

Categories: linux Tags:

Xen Hypervisor

January 29th, 2011 No comments

The Open Source Xen hypervisor runs directly on the hardware and becomes the interface for all hardware requests such as CPU, I/O, and disk for the guest operating systems.  By separating the guests from the hardware, the Xen hypervisor is able to run multiple operating systems securely and independently. Read more…

Categories: Computer Architecture Tags: ,

Kerberos Realms Usage

November 18th, 2010 No comments

In order to authenticate against Kerberos realms and perform remote administration, the system must have the krb5-workstation package installed. Read more…

Categories: Unix(*nix) Tags: ,

Using Network Grep (ngrep.exe) to Capture Traffic. (Filter on Payload!)

July 31st, 2010 No comments

ngrep is a “network grep” utility that can be used to match regular expressions within network packet payloads. This is a very handy utility as many network analysers (“packet sniffers”) can examine the packet header, but either do not display or cannot filter based on packet payload. Read more…

Install Linux on USB Drive – Unetbootin

March 28th, 2010 No comments

A simple point-and-click utility enabling you to automagically download and install a choice of Linux distributions.  Install Linux on USB partitions as small as 128Mb.

Read more…

Categories: linux Tags: